exiftool_metadata() crashes with FileNotFoundError when exiftool_path binary doesn't exist

[hanhan761]

Description

When exiftool_path is set but points to a non-existent binary, exiftool_metadata() crashes with an unhandled FileNotFoundError instead of returning an empty metadata dict or raising a clear error.

The subprocess.run() call on line 22 (and 41) raises FileNotFoundError when the binary is not found, but the except clause only catches CalledProcessError and ValueError.

Root Cause

packages/markitdown/src/markitdown/converters/_exiftool.py, lines 21-27:

try:
    version_output = subprocess.run(
        [exiftool_path, "-ver"],
        capture_output=True, text=True, check=True,
    ).stdout.strip()
    ...
except (subprocess.CalledProcessError, ValueError) as e:
    raise RuntimeError("Failed to verify ExifTool version.") from e

FileNotFoundError (when the binary doesn't exist) is a subclass of OSError, not CalledProcessError or ValueError, so it propagates uncaught.

Expected Behavior

If exiftool_path points to a non-existent file, exiftool_metadata() should return an empty dict (graceful degradation) rather than crashing the entire conversion.

Proposed Fix

Add OSError (parent of FileNotFoundError) to the except clause.